1 /*- 2 * Copyright (c) 1999-2002, 2006, 2009 Robert N. M. Watson 3 * Copyright (c) 2001 Ilmar S. Habibulin 4 * Copyright (c) 2001-2005 Networks Associates Technology, Inc. 5 * Copyright (c) 2005-2006 SPARTA, Inc. 6 * Copyright (c) 2008-2009 Apple Inc. 7 * All rights reserved. 8 * 9 * This software was developed by Robert Watson and Ilmar Habibulin for the 10 * TrustedBSD Project. 11 * 12 * This software was developed for the FreeBSD Project in part by Network 13 * Associates Laboratories, the Security Research Division of Network 14 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), 15 * as part of the DARPA CHATS research program. 16 * 17 * This software was enhanced by SPARTA ISSO under SPAWAR contract 18 * N66001-04-C-6019 ("SEFOS"). 19 * 20 * This software was developed at the University of Cambridge Computer 21 * Laboratory with support from a grant from Google, Inc. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the above copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 35 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 42 * SUCH DAMAGE. 43 */ 44 45 /*- 46 * Framework for extensible kernel access control. This file contains core 47 * kernel infrastructure for the TrustedBSD MAC Framework, including policy 48 * registration, versioning, locking, error composition operator, and system 49 * calls. 50 * 51 * The MAC Framework implements three programming interfaces: 52 * 53 * - The kernel MAC interface, defined in mac_framework.h, and invoked 54 * throughout the kernel to request security decisions, notify of security 55 * related events, etc. 56 * 57 * - The MAC policy module interface, defined in mac_policy.h, which is 58 * implemented by MAC policy modules and invoked by the MAC Framework to 59 * forward kernel security requests and notifications to policy modules. 60 * 61 * - The user MAC API, defined in mac.h, which allows user programs to query 62 * and set label state on objects. 63 * 64 * The majority of the MAC Framework implementation may be found in 65 * src/sys/security/mac. Sample policy modules may be found in 66 * src/sys/security/mac_*. 67 */ 68 69 #include "opt_mac.h" 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/condvar.h> 74 #include <sys/kernel.h> 75 #include <sys/lock.h> 76 #include <sys/mac.h> 77 #include <sys/module.h> 78 #include <sys/rmlock.h> 79 #include <sys/sdt.h> 80 #include <sys/sx.h> 81 #include <sys/sysctl.h> 82 #include <sys/vnode.h> 83 84 #include <security/mac/mac_framework.h> 85 #include <security/mac/mac_internal.h> 86 #include <security/mac/mac_policy.h> 87 88 /* 89 * DTrace SDT providers for MAC. 90 */ 91 SDT_PROVIDER_DEFINE(mac); 92 SDT_PROVIDER_DEFINE(mac_framework); 93 94 SDT_PROBE_DEFINE2(mac, , policy, modevent, "int", 95 "struct mac_policy_conf *"); 96 SDT_PROBE_DEFINE1(mac, , policy, register, 97 "struct mac_policy_conf *"); 98 SDT_PROBE_DEFINE1(mac, , policy, unregister, 99 "struct mac_policy_conf *"); 100 101 /* 102 * Root sysctl node for all MAC and MAC policy controls. 103 */ 104 SYSCTL_NODE(_security, OID_AUTO, mac, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 105 "TrustedBSD MAC policy controls"); 106 107 /* 108 * Declare that the kernel provides MAC support, version 3 (FreeBSD 7.x). 109 * This permits modules to refuse to be loaded if the necessary support isn't 110 * present, even if it's pre-boot. 111 */ 112 MODULE_VERSION(kernel_mac_support, MAC_VERSION); 113 114 static unsigned int mac_version = MAC_VERSION; 115 SYSCTL_UINT(_security_mac, OID_AUTO, version, CTLFLAG_RD, &mac_version, 0, 116 ""); 117 118 /* 119 * Flags for inlined checks. Note this would be best hotpatched at runtime. 120 * The following is a band-aid. 121 * 122 * Use FPFLAG for hooks running in commonly executed paths and FPFLAG_RARE 123 * for the rest. 124 */ 125 #define FPFLAG(f) \ 126 bool __read_frequently mac_##f##_fp_flag 127 128 #define FPFLAG_RARE(f) \ 129 bool __read_mostly mac_##f##_fp_flag 130 131 FPFLAG(priv_check); 132 FPFLAG(priv_grant); 133 FPFLAG(vnode_check_lookup); 134 FPFLAG(vnode_check_open); 135 FPFLAG(vnode_check_stat); 136 FPFLAG(vnode_check_read); 137 FPFLAG(vnode_check_write); 138 FPFLAG(vnode_check_mmap); 139 FPFLAG_RARE(vnode_check_poll); 140 FPFLAG_RARE(vnode_check_rename_from); 141 FPFLAG_RARE(vnode_check_access); 142 FPFLAG_RARE(vnode_check_readlink); 143 FPFLAG_RARE(pipe_check_stat); 144 FPFLAG_RARE(pipe_check_poll); 145 FPFLAG_RARE(pipe_check_read); 146 FPFLAG_RARE(ifnet_create_mbuf); 147 FPFLAG_RARE(ifnet_check_transmit); 148 149 #undef FPFLAG 150 #undef FPFLAG_RARE 151 152 /* 153 * Labels consist of a indexed set of "slots", which are allocated policies 154 * as required. The MAC Framework maintains a bitmask of slots allocated so 155 * far to prevent reuse. Slots cannot be reused, as the MAC Framework 156 * guarantees that newly allocated slots in labels will be NULL unless 157 * otherwise initialized, and because we do not have a mechanism to garbage 158 * collect slots on policy unload. As labeled policies tend to be statically 159 * loaded during boot, and not frequently unloaded and reloaded, this is not 160 * generally an issue. 161 */ 162 #if MAC_MAX_SLOTS > 32 163 #error "MAC_MAX_SLOTS too large" 164 #endif 165 166 static unsigned int mac_max_slots = MAC_MAX_SLOTS; 167 static unsigned int mac_slot_offsets_free = (1 << MAC_MAX_SLOTS) - 1; 168 SYSCTL_UINT(_security_mac, OID_AUTO, max_slots, CTLFLAG_RD, &mac_max_slots, 169 0, ""); 170 171 /* 172 * Has the kernel started generating labeled objects yet? All read/write 173 * access to this variable is serialized during the boot process. Following 174 * the end of serialization, we don't update this flag; no locking. 175 */ 176 static int mac_late = 0; 177 178 /* 179 * Each policy declares a mask of object types requiring labels to be 180 * allocated for them. For convenience, we combine and cache the bitwise or 181 * of the per-policy object flags to track whether we will allocate a label 182 * for an object type at run-time. 183 */ 184 uint64_t mac_labeled; 185 SYSCTL_UQUAD(_security_mac, OID_AUTO, labeled, CTLFLAG_RD, &mac_labeled, 0, 186 "Mask of object types being labeled"); 187 188 MALLOC_DEFINE(M_MACTEMP, "mactemp", "MAC temporary label storage"); 189 190 /* 191 * MAC policy modules are placed in one of two lists: mac_static_policy_list, 192 * for policies that are loaded early and cannot be unloaded, and 193 * mac_policy_list, which holds policies either loaded later in the boot 194 * cycle or that may be unloaded. The static policy list does not require 195 * locks to iterate over, but the dynamic list requires synchronization. 196 * Support for dynamic policy loading can be compiled out using the 197 * MAC_STATIC kernel option. 198 * 199 * The dynamic policy list is protected by two locks: modifying the list 200 * requires both locks to be held exclusively. One of the locks, 201 * mac_policy_rm, is acquired over policy entry points that will never sleep; 202 * the other, mac_policy_rms, is acquired over policy entry points that may 203 * sleep. The former category will be used when kernel locks may be held 204 * over calls to the MAC Framework, during network processing in ithreads, 205 * etc. The latter will tend to involve potentially blocking memory 206 * allocations, extended attribute I/O, etc. 207 */ 208 #ifndef MAC_STATIC 209 static struct rmlock mac_policy_rm; /* Non-sleeping entry points. */ 210 static struct rmslock mac_policy_rms; /* Sleeping entry points. */ 211 #endif 212 213 struct mac_policy_list_head mac_policy_list; 214 struct mac_policy_list_head mac_static_policy_list; 215 u_int mac_policy_count; /* Registered policy count. */ 216 217 static void mac_policy_xlock(void); 218 static void mac_policy_xlock_assert(void); 219 static void mac_policy_xunlock(void); 220 221 void 222 mac_policy_slock_nosleep(struct rm_priotracker *tracker) 223 { 224 225 #ifndef MAC_STATIC 226 if (!mac_late) 227 return; 228 229 rm_rlock(&mac_policy_rm, tracker); 230 #endif 231 } 232 233 void 234 mac_policy_slock_sleep(void) 235 { 236 237 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 238 "mac_policy_slock_sleep"); 239 240 #ifndef MAC_STATIC 241 if (!mac_late) 242 return; 243 244 rms_rlock(&mac_policy_rms); 245 #endif 246 } 247 248 void 249 mac_policy_sunlock_nosleep(struct rm_priotracker *tracker) 250 { 251 252 #ifndef MAC_STATIC 253 if (!mac_late) 254 return; 255 256 rm_runlock(&mac_policy_rm, tracker); 257 #endif 258 } 259 260 void 261 mac_policy_sunlock_sleep(void) 262 { 263 264 #ifndef MAC_STATIC 265 if (!mac_late) 266 return; 267 268 rms_runlock(&mac_policy_rms); 269 #endif 270 } 271 272 static void 273 mac_policy_xlock(void) 274 { 275 276 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 277 "mac_policy_xlock()"); 278 279 #ifndef MAC_STATIC 280 if (!mac_late) 281 return; 282 283 rms_wlock(&mac_policy_rms); 284 rm_wlock(&mac_policy_rm); 285 #endif 286 } 287 288 static void 289 mac_policy_xunlock(void) 290 { 291 292 #ifndef MAC_STATIC 293 if (!mac_late) 294 return; 295 296 rm_wunlock(&mac_policy_rm); 297 rms_wunlock(&mac_policy_rms); 298 #endif 299 } 300 301 static void 302 mac_policy_xlock_assert(void) 303 { 304 305 #ifndef MAC_STATIC 306 if (!mac_late) 307 return; 308 309 rm_assert(&mac_policy_rm, RA_WLOCKED); 310 #endif 311 } 312 313 /* 314 * Initialize the MAC subsystem, including appropriate SMP locks. 315 */ 316 static void 317 mac_init(void) 318 { 319 320 LIST_INIT(&mac_static_policy_list); 321 LIST_INIT(&mac_policy_list); 322 mac_labelzone_init(); 323 324 #ifndef MAC_STATIC 325 rm_init_flags(&mac_policy_rm, "mac_policy_rm", RM_NOWITNESS | 326 RM_RECURSE); 327 rms_init(&mac_policy_rms, "mac_policy_rms"); 328 #endif 329 } 330 331 /* 332 * For the purposes of modules that want to know if they were loaded "early", 333 * set the mac_late flag once we've processed modules either linked into the 334 * kernel, or loaded before the kernel startup. 335 */ 336 static void 337 mac_late_init(void) 338 { 339 340 mac_late = 1; 341 } 342 343 /* 344 * Given a policy, derive from its set of non-NULL label init methods what 345 * object types the policy is interested in. 346 */ 347 static uint64_t 348 mac_policy_getlabeled(struct mac_policy_conf *mpc) 349 { 350 uint64_t labeled; 351 352 #define MPC_FLAG(method, flag) \ 353 if (mpc->mpc_ops->mpo_ ## method != NULL) \ 354 labeled |= (flag); \ 355 356 labeled = 0; 357 MPC_FLAG(cred_init_label, MPC_OBJECT_CRED); 358 MPC_FLAG(proc_init_label, MPC_OBJECT_PROC); 359 MPC_FLAG(vnode_init_label, MPC_OBJECT_VNODE); 360 MPC_FLAG(inpcb_init_label, MPC_OBJECT_INPCB); 361 MPC_FLAG(socket_init_label, MPC_OBJECT_SOCKET); 362 MPC_FLAG(devfs_init_label, MPC_OBJECT_DEVFS); 363 MPC_FLAG(mbuf_init_label, MPC_OBJECT_MBUF); 364 MPC_FLAG(ipq_init_label, MPC_OBJECT_IPQ); 365 MPC_FLAG(ifnet_init_label, MPC_OBJECT_IFNET); 366 MPC_FLAG(bpfdesc_init_label, MPC_OBJECT_BPFDESC); 367 MPC_FLAG(pipe_init_label, MPC_OBJECT_PIPE); 368 MPC_FLAG(mount_init_label, MPC_OBJECT_MOUNT); 369 MPC_FLAG(posixsem_init_label, MPC_OBJECT_POSIXSEM); 370 MPC_FLAG(posixshm_init_label, MPC_OBJECT_POSIXSHM); 371 MPC_FLAG(sysvmsg_init_label, MPC_OBJECT_SYSVMSG); 372 MPC_FLAG(sysvmsq_init_label, MPC_OBJECT_SYSVMSQ); 373 MPC_FLAG(sysvsem_init_label, MPC_OBJECT_SYSVSEM); 374 MPC_FLAG(sysvshm_init_label, MPC_OBJECT_SYSVSHM); 375 MPC_FLAG(syncache_init_label, MPC_OBJECT_SYNCACHE); 376 MPC_FLAG(ip6q_init_label, MPC_OBJECT_IP6Q); 377 378 #undef MPC_FLAG 379 return (labeled); 380 } 381 382 /* 383 * When policies are loaded or unloaded, walk the list of registered policies 384 * and built mac_labeled, a bitmask representing the union of all objects 385 * requiring labels across all policies. 386 */ 387 static void 388 mac_policy_update(void) 389 { 390 struct mac_policy_conf *mpc; 391 392 mac_policy_xlock_assert(); 393 394 mac_labeled = 0; 395 mac_policy_count = 0; 396 LIST_FOREACH(mpc, &mac_static_policy_list, mpc_list) { 397 mac_labeled |= mac_policy_getlabeled(mpc); 398 mac_policy_count++; 399 } 400 LIST_FOREACH(mpc, &mac_policy_list, mpc_list) { 401 mac_labeled |= mac_policy_getlabeled(mpc); 402 mac_policy_count++; 403 } 404 405 cache_fast_lookup_enabled_recalc(); 406 } 407 408 /* 409 * There are frequently used code paths which check for rarely installed 410 * policies. Gross hack below enables doing it in a cheap manner. 411 */ 412 413 #define FPO(f) (offsetof(struct mac_policy_ops, mpo_##f) / sizeof(uintptr_t)) 414 415 struct mac_policy_fastpath_elem { 416 int count; 417 bool *flag; 418 size_t offset; 419 }; 420 421 struct mac_policy_fastpath_elem mac_policy_fastpath_array[] = { 422 { .offset = FPO(priv_check), .flag = &mac_priv_check_fp_flag }, 423 { .offset = FPO(priv_grant), .flag = &mac_priv_grant_fp_flag }, 424 { .offset = FPO(vnode_check_lookup), 425 .flag = &mac_vnode_check_lookup_fp_flag }, 426 { .offset = FPO(vnode_check_readlink), 427 .flag = &mac_vnode_check_readlink_fp_flag }, 428 { .offset = FPO(vnode_check_open), 429 .flag = &mac_vnode_check_open_fp_flag }, 430 { .offset = FPO(vnode_check_stat), 431 .flag = &mac_vnode_check_stat_fp_flag }, 432 { .offset = FPO(vnode_check_read), 433 .flag = &mac_vnode_check_read_fp_flag }, 434 { .offset = FPO(vnode_check_write), 435 .flag = &mac_vnode_check_write_fp_flag }, 436 { .offset = FPO(vnode_check_mmap), 437 .flag = &mac_vnode_check_mmap_fp_flag }, 438 { .offset = FPO(vnode_check_poll), 439 .flag = &mac_vnode_check_poll_fp_flag }, 440 { .offset = FPO(vnode_check_rename_from), 441 .flag = &mac_vnode_check_rename_from_fp_flag }, 442 { .offset = FPO(vnode_check_access), 443 .flag = &mac_vnode_check_access_fp_flag }, 444 { .offset = FPO(pipe_check_stat), 445 .flag = &mac_pipe_check_stat_fp_flag }, 446 { .offset = FPO(pipe_check_poll), 447 .flag = &mac_pipe_check_poll_fp_flag }, 448 { .offset = FPO(pipe_check_read), 449 .flag = &mac_pipe_check_read_fp_flag }, 450 { .offset = FPO(ifnet_create_mbuf), 451 .flag = &mac_ifnet_create_mbuf_fp_flag }, 452 { .offset = FPO(ifnet_check_transmit), 453 .flag = &mac_ifnet_check_transmit_fp_flag }, 454 }; 455 456 static void 457 mac_policy_fastpath_enable(struct mac_policy_fastpath_elem *mpfe) 458 { 459 460 MPASS(mpfe->count >= 0); 461 mpfe->count++; 462 if (mpfe->count == 1) { 463 MPASS(*mpfe->flag == false); 464 *mpfe->flag = true; 465 } 466 } 467 468 static void 469 mac_policy_fastpath_disable(struct mac_policy_fastpath_elem *mpfe) 470 { 471 472 MPASS(mpfe->count >= 1); 473 mpfe->count--; 474 if (mpfe->count == 0) { 475 MPASS(*mpfe->flag == true); 476 *mpfe->flag = false; 477 } 478 } 479 480 static void 481 mac_policy_fastpath_register(struct mac_policy_conf *mpc) 482 { 483 struct mac_policy_fastpath_elem *mpfe; 484 uintptr_t **ops; 485 int i; 486 487 mac_policy_xlock_assert(); 488 489 ops = (uintptr_t **)mpc->mpc_ops; 490 for (i = 0; i < nitems(mac_policy_fastpath_array); i++) { 491 mpfe = &mac_policy_fastpath_array[i]; 492 if (ops[mpfe->offset] != NULL) 493 mac_policy_fastpath_enable(mpfe); 494 } 495 } 496 497 static void 498 mac_policy_fastpath_unregister(struct mac_policy_conf *mpc) 499 { 500 struct mac_policy_fastpath_elem *mpfe; 501 uintptr_t **ops; 502 int i; 503 504 mac_policy_xlock_assert(); 505 506 ops = (uintptr_t **)mpc->mpc_ops; 507 for (i = 0; i < nitems(mac_policy_fastpath_array); i++) { 508 mpfe = &mac_policy_fastpath_array[i]; 509 if (ops[mpfe->offset] != NULL) 510 mac_policy_fastpath_disable(mpfe); 511 } 512 } 513 514 #undef FPO 515 516 static int 517 mac_policy_register(struct mac_policy_conf *mpc) 518 { 519 struct mac_policy_list_head *mpc_list; 520 struct mac_policy_conf *last_mpc, *tmpc; 521 int error, slot, static_entry; 522 523 error = 0; 524 525 /* 526 * We don't technically need exclusive access while !mac_late, but 527 * hold it for assertion consistency. 528 */ 529 mac_policy_xlock(); 530 531 /* 532 * If the module can potentially be unloaded, or we're loading late, 533 * we have to stick it in the non-static list and pay an extra 534 * performance overhead. Otherwise, we can pay a light locking cost 535 * and stick it in the static list. 536 */ 537 static_entry = (!mac_late && 538 !(mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_UNLOADOK)); 539 540 mpc_list = (static_entry) ? &mac_static_policy_list : 541 &mac_policy_list; 542 last_mpc = NULL; 543 LIST_FOREACH(tmpc, mpc_list, mpc_list) { 544 last_mpc = tmpc; 545 if (strcmp(tmpc->mpc_name, mpc->mpc_name) == 0) { 546 error = EEXIST; 547 goto out; 548 } 549 } 550 if (mpc->mpc_field_off != NULL) { 551 slot = ffs(mac_slot_offsets_free); 552 if (slot == 0) { 553 error = ENOMEM; 554 goto out; 555 } 556 slot--; 557 mac_slot_offsets_free &= ~(1 << slot); 558 *mpc->mpc_field_off = slot; 559 } 560 mpc->mpc_runtime_flags |= MPC_RUNTIME_FLAG_REGISTERED; 561 562 /* 563 * Some modules may depend on the operations of its dependencies. 564 * Inserting modules in order of registration ensures operations 565 * that work on the module list retain dependency order. 566 */ 567 if (last_mpc == NULL) 568 LIST_INSERT_HEAD(mpc_list, mpc, mpc_list); 569 else 570 LIST_INSERT_AFTER(last_mpc, mpc, mpc_list); 571 /* 572 * Per-policy initialization. Currently, this takes place under the 573 * exclusive lock, so policies must not sleep in their init method. 574 * In the future, we may want to separate "init" from "start", with 575 * "init" occurring without the lock held. Likewise, on tear-down, 576 * breaking out "stop" from "destroy". 577 */ 578 if (mpc->mpc_ops->mpo_init != NULL) 579 (*(mpc->mpc_ops->mpo_init))(mpc); 580 581 mac_policy_fastpath_register(mpc); 582 583 mac_policy_update(); 584 585 SDT_PROBE1(mac, , policy, register, mpc); 586 printf("Security policy loaded: %s (%s)\n", mpc->mpc_fullname, 587 mpc->mpc_name); 588 589 out: 590 mac_policy_xunlock(); 591 return (error); 592 } 593 594 static int 595 mac_policy_unregister(struct mac_policy_conf *mpc) 596 { 597 598 /* 599 * If we fail the load, we may get a request to unload. Check to see 600 * if we did the run-time registration, and if not, silently succeed. 601 */ 602 mac_policy_xlock(); 603 if ((mpc->mpc_runtime_flags & MPC_RUNTIME_FLAG_REGISTERED) == 0) { 604 mac_policy_xunlock(); 605 return (0); 606 } 607 #if 0 608 /* 609 * Don't allow unloading modules with private data. 610 */ 611 if (mpc->mpc_field_off != NULL) { 612 mac_policy_xunlock(); 613 return (EBUSY); 614 } 615 #endif 616 /* 617 * Only allow the unload to proceed if the module is unloadable by 618 * its own definition. 619 */ 620 if ((mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_UNLOADOK) == 0) { 621 mac_policy_xunlock(); 622 return (EBUSY); 623 } 624 625 mac_policy_fastpath_unregister(mpc); 626 627 if (mpc->mpc_ops->mpo_destroy != NULL) 628 (*(mpc->mpc_ops->mpo_destroy))(mpc); 629 630 LIST_REMOVE(mpc, mpc_list); 631 mpc->mpc_runtime_flags &= ~MPC_RUNTIME_FLAG_REGISTERED; 632 mac_policy_update(); 633 mac_policy_xunlock(); 634 635 SDT_PROBE1(mac, , policy, unregister, mpc); 636 printf("Security policy unload: %s (%s)\n", mpc->mpc_fullname, 637 mpc->mpc_name); 638 639 return (0); 640 } 641 642 /* 643 * Allow MAC policy modules to register during boot, etc. 644 */ 645 int 646 mac_policy_modevent(module_t mod, int type, void *data) 647 { 648 struct mac_policy_conf *mpc; 649 int error; 650 651 error = 0; 652 mpc = (struct mac_policy_conf *) data; 653 654 #ifdef MAC_STATIC 655 if (mac_late) { 656 printf("mac_policy_modevent: MAC_STATIC and late\n"); 657 return (EBUSY); 658 } 659 #endif 660 661 SDT_PROBE2(mac, , policy, modevent, type, mpc); 662 switch (type) { 663 case MOD_LOAD: 664 if (mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_NOTLATE && 665 mac_late) { 666 printf("mac_policy_modevent: can't load %s policy " 667 "after booting\n", mpc->mpc_name); 668 error = EBUSY; 669 break; 670 } 671 error = mac_policy_register(mpc); 672 break; 673 case MOD_UNLOAD: 674 /* Don't unregister the module if it was never registered. */ 675 if ((mpc->mpc_runtime_flags & MPC_RUNTIME_FLAG_REGISTERED) 676 != 0) 677 error = mac_policy_unregister(mpc); 678 else 679 error = 0; 680 break; 681 default: 682 error = EOPNOTSUPP; 683 break; 684 } 685 686 return (error); 687 } 688 689 /* 690 * Define an error value precedence, and given two arguments, selects the 691 * value with the higher precedence. 692 */ 693 int 694 mac_error_select(int error1, int error2) 695 { 696 697 /* Certain decision-making errors take top priority. */ 698 if (error1 == EDEADLK || error2 == EDEADLK) 699 return (EDEADLK); 700 701 /* Invalid arguments should be reported where possible. */ 702 if (error1 == EINVAL || error2 == EINVAL) 703 return (EINVAL); 704 705 /* Precedence goes to "visibility", with both process and file. */ 706 if (error1 == ESRCH || error2 == ESRCH) 707 return (ESRCH); 708 709 if (error1 == ENOENT || error2 == ENOENT) 710 return (ENOENT); 711 712 /* Precedence goes to DAC/MAC protections. */ 713 if (error1 == EACCES || error2 == EACCES) 714 return (EACCES); 715 716 /* Precedence goes to privilege. */ 717 if (error1 == EPERM || error2 == EPERM) 718 return (EPERM); 719 720 /* Precedence goes to error over success; otherwise, arbitrary. */ 721 if (error1 != 0) 722 return (error1); 723 return (error2); 724 } 725 726 int 727 mac_check_structmac_consistent(const struct mac *mac) 728 { 729 /* Require that labels have a non-zero length. */ 730 if (mac->m_buflen > MAC_MAX_LABEL_BUF_LEN || 731 mac->m_buflen <= sizeof("")) 732 return (EINVAL); 733 734 return (0); 735 } 736 737 SYSINIT(mac, SI_SUB_MAC, SI_ORDER_FIRST, mac_init, NULL); 738 SYSINIT(mac_late, SI_SUB_MAC_LATE, SI_ORDER_FIRST, mac_late_init, NULL); 739